Active Directory Certificate Services (AD CS) provides customizable services for issuing and managing public key certificates used in software security systems that employ public key technologies. With strong security and easy administration across the Internet,
extranets, intranets, and applications, AD CS provides customizable services for issuing and managing the certificates used in software security systems employing public key technologies. AD CS allows you to move beyond traditional username and password combinations
for more robust authentication and resource access security. By installing Active Directory Certificate Services (AD CS), you are either creating or extending a Public Key Infrastructure (PKI). A PKI structure that meets the requirements of most organizations
is a multi-tier Certification Authority (CA) hierarchy that implements an
Offline Root CA. For more information, see the
Windows PKI documentation and reference library.

If you are new to AD CS, this topic can help you identify what you need to learn to fully understand AD CS. Ensure that you first understand the prerequisite topics, because the later AD CS topics build upon as well as assume an understanding of the prerequisites.
Afterwards, you can begin learning about AD CS through the resources in the Level 100 (introductory), 200 (intermediate), and 300 (advanced) sections.